Rework quick unlock settings to follow new specs.

chrome/browser/resources/settings/people_page/lock_state_behavior.js

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+/**
+ * @fileoverview
+ * Contains utilities that help identify the current way that the lock screen
+ * will be displayed.
+ */
+
+/** @enum {string} */
+var LockScreenUnlockType = {
+  VALUE_PENDING: 'value_pending',
+  PASSWORD: 'password',
+  PIN_PASSWORD: 'pin+password'
+};
+
+/** @polymerBehavior */
+var LockStateBehavior = {
+  properties: {
+    /**
+     * The currently selected unlock type.
+     * @type {!LockScreenUnlockType}
+     */
+    selectedUnlockType: {
+      type: String,
+      notify: true,
+      value: LockScreenUnlockType.VALUE_PENDING
+    },
+
+    /**
+     * True/false if there is a PIN set; undefined if the computation is still
+     * pending. This is a separate value from selectedUnlockType because the UI
+     * can change the selectedUnlockType before setting up a PIN.
+     * @type {boolean|undefined}
+     */
+    hasPin: {

[tommycli, 2016/08/05 17:46:19]

Maybe this is no longer needed if selecting the last radio box automatically
opens the dialog?

[jdufault, 2016/08/05 20:59:52]

Right! But unfortunately that's not the desired behavior :(

+      type: Boolean,
+      notify: true
+    }
+  },
+
+  /** @override */
+  attached: function() {
+    this.boundOnActiveModesChanged_ = this.updateUnlockType_.bind(this);
+    chrome.quickUnlockPrivate.onActiveModesChanged.addListener(
+        this.boundOnActiveModesChanged_);
+
+    this.updateUnlockType_();
+  },
+
+  /** @override */
+  detached: function() {
+    chrome.quickUnlockPrivate.onActiveModesChanged.removeListener(
+        this.boundOnActiveModesChanged_);
+  },
+
+  /**
+   * Updates the selected unlock type radio group. This function will get called
+   * after preferences are initialized, after the quick unlock mode has been
+   * changed, and after the lockscreen preference has changed.
+   *
+   * @private
+   */
+  updateUnlockType_: function() {
+    chrome.quickUnlockPrivate.getActiveModes(function(modes) {
+      if (modes.includes(chrome.quickUnlockPrivate.QuickUnlockMode.PIN)) {
+        this.hasPin = true;
+        this.selectedUnlockType = LockScreenUnlockType.PIN_PASSWORD;
+      } else {
+        this.hasPin = false;
+        this.selectedUnlockType = LockScreenUnlockType.PASSWORD;
+      }
+    }.bind(this));
+  },
+};